An inventive format--a chapter book illustrated in full color with Stevenson's appealing figures--is sadly used by awkward writing and an odd piece of plotting. Ruthann has a pig whom, after trying many names, she calls Henry Thomas. How she got the pig, and how that pig became tame, are the source of a subplot, as is the sudden appearance of Ruthann's long-lost grandfather. The story's main thread involves Ruthann's cousin Frank, who would like to borrow Henry Thomas for his own purposes (he wants to set a bully straight by alluding to Henry Thomas as an attack pig). Ruthann doesn't want to lend Henry Thomas out and, to her credit, Porte doesn't make the girl a goody-two-shoes. But the solution presented instead is less than comic. Porte's present tense discourse jars, and is full of somewhat cynical asides. Ages 7-10. (Sept.)